Computer components

Seminar 1

The computer

Computers are electronic machines that process information. They are capable of communicating with the user, of doing five kinds of arithmetic operations, and of making three kinds of decision. However, they are incapable of thinking. They accept data and instruction as input, and after processing the information, they output the results.

When talking about computers, both hardware and software need to be considered. The former refers to the actual machinery, whereas the latter refers to the programs that control and coordinate the activities of the hardware.

The first computer was built in 1930 but since then computer technology has evolved a great deal. There are three different kinds of computers in use today: the mainframe, the minicomputer and the microcomputer. All three have one thing in common - they operate quickly and accurately in solving problems.

Computer components

A computer has four basic components: input, processor, memory and output. The processor has two parts: the control unit which directs the controls and controls the signal and commands inside the processor, and the arithmetic-logical unit which does the five arithmetic operations and the three decision-making operations.

In a computer, internal memory or primary memory refers to the storage locations inside the computer whereas secondary memory refers to the storage embodied in the peripherals. There are three types of internal memory: core, as in the mainframes; semiconductor or chip, as in microcomputers; and bubble memory. Secondary memory, on the other hand, may be classified as either sequential (tape) or direct-access (disk).

The input device, whether they are card readers, tape drives, disk drives, or terminals, enter the information into the computer. Alter the processor has operated on it, the output devices display the results of the computations on a printer or a terminal, or store them on tape or disk.

What is a computer?

When you read the following text, you will probably meet words and expressions that are new to you. First try to understand their meaning from the context - read the same passage р few times. When you have read the hole text, check new words in р dictionary. Those words in bold typeface are explained in the Glossary at the end of this book.

1. A computer is a machine with an intricate network of electronic circuits that operates switches or magnetizes tiny metal cores. The switches, like the cores, are capable of being in one of two possible states, that is, on or off, magnetized or demagnetized. The machine is capable of storing and manipulating numbers, letters, and characters. The basic idea of a computer is that we can make the machine do that we want by inputting signals that turn certain switches on and turn others off, or that magnetize or do not magnetize the cores.

2. The basic job of computers is the processing of information. For this reason, computers can be defined as devices which accept information in the form of instructions called a program and characters called data, perform mathematical and/or logical operations on the information, and than supply results of these operations. The program, or part of it, which tells the computers what to do and the data, which provide the information needed to solve the problem, are kept inside the computer in a place called memory.

3. Computers are thought to have many remarkable powers. However, most computers, whether large or small have three basic capabilities. First, computers have circuits for performing arithmetic operations, such as: addition, subtraction, division, multiplication and exponentiation. Second, computers have a means of communication with the user. After all, if we couldn’t feed information in and get results back, these machines wouldn’t be of much use. However, certain computers (commonly minicomputers and microcomputers) are used to control directly things such as robots, aircraft navigation system, medical instruments, etc.

4. Some of the most common methods of inputting information are to use punched cards, magnetic tape, disks and terminals. The computer's input devise (which might be a card reader, a tape drive or disk drive, depending on the medium used in inputting information) reads the information into the computer. For outputting information, two common devices used are a printer which prints the new information on paper, or a CRT display screen which shows the results on a TV-like screen.

5. Third, computers have circuits which can make decisions. The kinds of decisions which computer circuits can make are not of the type: "Who would win a war between two computers?" or "Who is the richest person in the world?". Unfortunately, the computer can only decide three things, namely: Is one number less than another? Are two numbers equal? And, Is one number greater than another?

6. A computer can solve a series problems and make hundreds, even thousands, of logical decisions without becoming tired or bored. It can find the solution to a problem in a fraction of the time it takes a human being to do the job. A computer can replace people in dull, routine tasks, but it has no originality; it works according to the instructions given to it and cannot exercise any value judgments. There are times when a computer seems to operate like a mechanical "brain", but its achievements are limited by the minds of human beings. A computer cannot do anything unless a person tells it what to do and gives to the appropriate information; but because electric pulses can move at the speed of light, a computer can carry out vast numbers of arithmetic-logical operations almost instantaneously. A person can do everything a computer can do, but it many cases that person would be dead long before the job was finished.

Excises

Main idea

Which statement best expresses the main idea of the text? Why did you eliminate the other choices?

__ 1. Computers have changed the way in which many kinds of jobs are done.

__ 2. Instructions and data must be given to the computer to act on.

__ 3. Computers are machines capable of processing and outputting data.

__ 4. Without computers, many tasks would take much longer to do.

Не нашли, что искали? Воспользуйтесь поиском: